1. Field of the Invention
This invention relates generally to ports for injecting fluids into an intravenous (IV) line, and more specifically to injection manifolds including multiple injection ports.
2. Discussion of the Prior Art
Patients are commonly injected with IV solutions which are initially provided in a bottle or bag and dripped into the vein of the patient through an IV line. Typically an injection port is provided along the line and adapted to function with a syringe to permit an injectate to be added to the IV solution. If a large quantity of injectate, or multiple injectates, are to be added to the IV solution, multiple ports may be required. In such a case, an injection manifold can be disposed in the IV line to provide multiple injectate ports.
A check valve is also commonly included in the IV line where it is disposed upstream from the injection manifold. It is the purpose of the check valve to permit fluid flow only in the direction of the patient. This ensures that the injectate flows downstream toward the patient, not upstream toward the IV reservoir.
In the past, IV manifolds have been provided with an elongate and generally flat configuration in order to facilitate use of the multiple injection ports. The flow channel through the manifold has also had this elongate wide configuration, and consequently, has been susceptible to the formation of air pockets and to generally uneven flow characteristics. In the vicinity of the injection ports, the manifolds of the past have also developed dead spaces where the injectate has tended to collect rather than mix with the IV solution. Other IV manifolds have been provided with a round tube defing the flow channel. Injection ports have been connected to this tube at a xe2x80x9cTxe2x80x9d junction. In this case, the flow channel has reamined separate and the problems with dead spaces in the ports have been significant.
Injection ports of the past have generally included only valves with a single valve seal. These seals have not been capable of withstanding high pressure such as those sometimes associated with an injection into an adjacent port. The resulting high back pressure has sometimes caused the valve element to deform and lodge in the lumen of the port, rendering the port inoperative.
In the past, the ports associated with injection manifold have not been provided with characteristics permitting the aspiration of fluids from the flow channel. This is sometimes desirable in order to remove air from the manifold or withdraw a blood sample. In these cases, a separate aspiration port has been required in addition to the injection manifold.
Some injection ports have been provided with operative cages which mechanically open the valves. In this case a syringe having a male Luer fitting is relied on to push the cage against the valve element in order to open the valve. Due to wide tolerance variations in the plastic parts associated with the syringes, the male Luer fittings can sometimes extend into the injection port a distance greater than that required to open the valve. In many of these cases, damage to the injection port has resulted.
These problems with the injection ports and manifolds of the prior art are overcome with the present invention which provides for a generally U-shaped flow channel that extends axially of the manifold. By restricting the IV solution to this flow channel, the flow characteristics through the manifold are greatly enhanced. Importantly, there are no dead spots in the fluid flow through the manifold. Furthermore, the flow of fluid can be directed against the valve element of the injection port to avoid dead spots around the valve. A check valve can be included in this manifold and disposed at one end of the elongate housing. An infusion/aspiration port is preferably disposed upstream of the other injection ports and downstream of the check valve.
A preferred injection port is provided with two seals, a line seal and a surface seal, which provide for low pressure and high pressure operation, respectively. When an injectate is being introduced into an adjacent port, the resulting high back pressure is resisted by the high pressure surface seal of the port.
In an injection port embodiment including a cage, the cage can be configured to be axially compressible. These compressible characteristics accommodate the wide tolerance variations in the plastic parts which sometimes tend to cause a male Luer fitting to extend into the injection port a distance greater than that necessary to open the associated valve. By providing the cage with these compressible characteristics, the tolerance variations are accommodated without damaging the valve element.
In one aspect, the invention includes an injection port adapted for use with an IV line. The port includes a housing defining a flow channel and having an injection lumen. First portions of the housing define a first valve seat, while second portions of the housing define a second valve seat. A valve element, disposed to extend transverse to the injection lumen has properties for forming a first seal with the first valve seat at a first pressure, and a second seal with the second valve seat at a second pressure greater than the first pressure. The first valve seat, which forms part of the second valve seat, has the shape of a continuous line, while the second valve seat has the shape of a continuous surface.
In another aspect, the invention includes a port for injecting an injectate into a flow channel for aspirating a fluid from the flow channel. The port includes a housing defining the flow channel and having a lumen disposed in fluid communication with the flow channel. First portions of the housing define a first valve seat while second portions of the housing define a second valve seat. A valve element has properties for forming a first seal with the first valve seat and a second seal with the second valve seat when the valve element is in a natural state. The valve element has properties for opening the first seal in response to a positive pressure in the lumen to facilitate flow of an injectate into the flow channel. The valve element also has properties for opening the second seal in response to a negative pressure in the lumen in order to facilitate flow of the fluid from the flow channel into the lumen of the port. The first valve seat is formed on the side of the valve element opposite the flow channel. The second valve seat is formed on the side of valve element opposite the first valve seat. This embodiment may include a post with the second seal being formed around the post.
In an additional aspect of the invention an injection manifold includes a first body member and second body member forming a housing. First portions of the housing define a flow channel adapted to receive an IV solution flowing in an IV line. Second portions of the housing define at least one port with an injection lumen, the port having a outside diameter. The first portions of the housing have a width greater than the outside diameter of the port and define the flow channel with a width less than the diameter of the port. The flow channel will typically have a U-shaped configuration.
In a further aspect of the invention an injection/aspiration port includes a housing with first portions defining a flow channel and second portions defining an injection/aspiration lumen. Third portions of the housing define a valve seat around the lumen. A valve element is biased toward the injection/aspiration lumen and forms a seal with the valve seat. A valve cage is disposed in the lumen and adapted to be moved by insertion of a male Luer fitting into the lumen against the valve element to open the seal and permit two-way flow between the lumen and the flow channel. The valve cage is axially compressible to accommodate slight variations in the size of the male Luer fitting.
These and other features and advantages of the present invention will be more apparent with a description of preferred embodiments and reference to the associated drawings.